Time and Frequency Measurement

I've always been interested in the technology used to measure things very
accurately, and as a ham radio operator, my focus rapidly became measuring
frequency, and its inverse, time (or is it the other way around?) to the
Nth degree. In particular, I'm interested in how radio can be used to
make precise time and frequency information available to end users. This
page has some details of my current experiments.

Below are links to some general areas in which I've experimented. Most
of my data and results are at
www.febo.com/pages.
This includes not only purely time and frequency related materials, but also
stuff from my more general Geekworks pages as well;
there's a lot of overlap between the two topics.

Going to www.febo.com/pages will show you a list of
directories; clicking on one will take you to its contents. Some of the
directories will be full-blown web pages, others may contain just some
pictures or plots, or further subdirectories containing who knows what.

I have written a bunch of scripts to automagically generate and update
charts from my data logging experiments. You can see the results:

www.febo.com/time-freq/plots
has phase plots of my frequency standards versus GPS and other experiments.
It also has charts monitoring temperature in my lab, and the signal
strength my GPS receivers are seeing.

NOTE: I've recently relocated and had to pack up my lab. Until
I get things going again, this is old data.

I've written some programs that do the work of generating these plots.
You can learn about them, and grab them for yourself, at
www.febo.com/time-freq/tools.

There are three principal methods used to disseminate time and frequency
information from national standards institutes to end users. They are:
(a) VLF radio stations like WWVB; (b) the LORAN-C navigation system; and
(c) GPS satellites (there are numerous other systems that have been
used, but they are either obsolete, very specialized, or of relatively low
performance). I've been experimenting with all three, and there's a page
here for each: